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Carbamazepine Epoxide and Total
0092211
Ordering Recommendation

Optimize drug therapy and monitor patient adherence.

Mnemonic
CARB EPOXT
Methodology
Quantitative Liquid Chromatography-Tandem Mass Spectrometry
Performed
Mon
Reported
1-8 days
New York DOH Approval Status
This test is New York DOH approved.
Submit With Order
ARUP Consult®
Disease Topics
Specimen Required
Patient Preparation
Timing of specimen collection: Pre-dose (trough) draw - At steady state concentration. 
Collect
Plain red. Also acceptable: Lavender (K2 or K3EDTA) or pink (K2EDTA). 
Specimen Preparation
Separate serum or plasma from cells within 2 hours of collection. Transfer 1 mL serum or plasma to an ARUP Standard Transport Tube. (Min: 0.5 mL) 
Storage/Transport Temperature
Frozen 
Unacceptable Conditions
Whole blood. Gel separator tubes, light blue (citrate), or yellow (SPS or ACD solution). 
Remarks
 
Stability
After separation from cells: Ambient: 48 hours; Refrigerated: 1 week; Frozen: 1 month 
Reference Interval
Effective November 13, 2017
Available Separately
Components
Therapeutic Range
NoCarbamazepine-10, 11 EpoxideNot well established
Toxic:  Greater than 15.0 µg/mL
NoTotal CarbamazepineTherapeutic Range: 4.0-12.0 µg/mL
Toxic:  Greater than 15.0 µg/mL

Interpretive Data
The therapeutic range is based on serum pre-dose (trough) draw at steady-state concentration. The carbamazepine metabolite, Carbamazepine-10, 11-Epoxide, has anticonvulsant activity and a proposed therapeutic range of 0.4-4 µL/mL.

A rare, adverse drug reaction to carbamazepine therapy includes Stevens-Johnson syndrome or toxic epidermal necrolysis. Patients of Asian ancestry with the presence of the HLA-B*15:02 have an increased risk for this carbamazepine-induced, life-threatening reaction. Pharmacogenetic testing for HLA-B*15:02 is recommended prior to treatment for patients at risk of carbamazepine hypersensitivity. This information has been included in the FDA-approved label for carbamazepine (<https://www.accessdata.fda.gov/scripts/cder/daf/index.cfm?event=overview.process&varApplNo=016608>) and in the guideline from the Clinical Pharmacogenetics Implementation Consortium (https://www.pharmgkb.org/guidelines). (HLA-B*15:02 Genotyping, Carbamazepine Hypersensitivity, ARUP test code 2012049.)

A combination of therapeutic drug monitoring with HLA-B*15:02 pharmacogenetics genotyping may benefit patients at increased risk of developing carbamazepine-induced adverse events due to rare genotypes other than the HLA-B*15:02 variant allele.

Compliance Statement B: For laboratory developed tests not using a RUO kit, and for FDA approved, cleared or 510(k) exempt assays with alterations. This test was developed and its performance characteristics determined by ARUP Laboratories. The U. S. Food and Drug Administration has not approved or cleared this test; however, FDA clearance or approval is not currently required for clinical use. The results are not intended to be used as the sole means for clinical diagnosis or patient management decisions.

Note
Hotline History
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Components
Component Test Code*Component Chart NameLOINC
0090616Carbamazepine, Total3432-2
0098427Carbamazepine 10-11 Epoxide9415-1
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.
Aliases
  • 11 Epoxide
  • Atretol
  • Biston
  • Calepsin
  • Carbamazepine - 10,11 Epoxide, Serum or Plasma
  • Carbamazepine and Epoxide Metabolite
  • Carbamazepine Metabolite
  • Carbamazepine-10
  • Carbatrol
  • Epimaz
  • Epitol
  • Epitrol
  • Epoxide 10, 11
  • Equetro
  • Finlepsin
  • Sirtal
  • Tegretol, Metabolite
  • Telesmin